Grinding machine



Oat.v 21, 1947. c. A. WIKEN El AL 2,429,250

GRINDING MACHINE v Filed June 22, 1945 1s Sheets-Sheet 1 M J MWS Ot. 21,1947. c. A. WIKEN ET AL 2,429,250

GRINDING MACHINE Filed June 22, 1943 13 Sheets-Sheet 2 M KM Oct. 21,'1947. c. A. WIKEN ET AL GRINDING MACHINE Fi1ed.June 22, 1943 13Sheets-Sheet 3 5 MV 5. A W W PM.

Oct. 21, 1947. 'C, MKEN ET AL 2,429,250

GRINDING MACHINE Filed June 22, 1943 l3 Sheets-Sheet 5 In f w HL .z -ZU.Z 24 i 69 z; mmml 7/ 4W5) 2! i; 7

CirzisyAQ men Eric/126%? Oct. 21, 1947. c. A. WIKEN ET AL 2,429,250

GRINDING MACHINE Filed June 22, 1943 13 Sheets-Sheet 6 Oct. 21, 1947. c.A. WIKEN ET AL eimmme MACHINE Filed June 22, 1943 13 Sheets-Sheet 8-GRINDING MACHINE l3 Sheets-Sheet 10 Filed June 22, 1943 och-21', 1941.c, A, KEN m 2,429,250

GRINDING MACHINE Filed JQIIG 2 2, 1943 I 13 Sheets-Sheet 11 Oct. 21,1947.. c. A. WIKEN El AL GRINDING MACHINE Filed June 22, 194:2: 13Sheets-Sheet 12 WMZM MNMMN Oct. 21, 1947. c. A. WIKEN ET AL GRINDINGMACHINE l3 Sheets-Sheet 13 Filed June 22, 1943 Patented Oct. 21, 1%47stares GRINDING MACHINE Application June 22, 1943, Serial No. 491,824

9 Claims.

The present invention relates to machine tools and is more particularlyconcerned with grinding machines having a device for carrying a rotarytool, supported on centers, past a grinding wheel for sharpening thecutting edges, although it is not limited to such use, inasmuch ascertain features are capable of advantageous utilization in othermachines.

Although machines of this general character have been heretoforeproposed, and some of them have gone into use, they are complicated andcostly, and moreover are of special construction, embodying a permanentheadstock and tailstock assembly adapting the machines solely to thegrinding of work between centers, and by reason of their design theycannot be successfully utilized to carry out other grinding operations.It has accordingly been impracticable for the owner of a small shop tomake the substantial invest ment required to purchase the prior tool andcutter sharpening machines, especially since they would be idle exceptwhen tool or cutter sharpening jobs were actually being carried out.Small shops have therefore sent out their tool and cutter sharpeningwork to shops having special machines designed for that purpose.

It is accordingly the primary object of this invention to provide agrinding machine having a tool holder assembly for carrying a tool orcutter past the grinding wheel, which will accurately hold the tool inproper position during grinding, permits readly indexing of the tool, tosuccessively present its cutting edges of the wheel, and is so designedthat the tool holder assembly may be completely removed and the machineemployed for surface or other classes of grinding operations.

A further important object is to provide a tool holding and centeringdevice which is so designed that it may be installed on the tables ofexisting grinding machine as an attachment, will rigidly and accuratelyhold tools in proper grinding position, may be readily removed torestore the grinding machine to its original condition, and yet which isof low cost, rugged construction.

Another object is' to provide an auxiliary table assembly, embodyingcenters for holding a tool, with a pilot assembly adapting it for securemounting on the tables of existing grinding machines, in any one of aplurality of angular adjusted positions about an axis normal to thetable surface, for sharpening tools having diflerently inclined cuttingedges.

A further object is to provide an auxiliary table adapted to beinstalled on the flat table of existing grinding machines and havingflat accurately-formed bearing surfaces on its lower side adapted torest on the table and a fiat top hearing surface on its upper sideadapted to adjustably support a headstock and a tailstock, the bearingsurfaces lying in parallel planesand the auxiliary table having noportions lying outside those planes, whereby the table may be accuratelyfinished in a simple surface grinding operation, eliminating handfinishing.

Another object is to provide a tool holding assembly embodying a,headstock and a tailstock which are of substantially identicalconstruction, it being only necessary to interchange certain minor partsto convert one to the other.

A further object is to provide a grinding machine, having a tablemovable in a horizontal plane under the wheel, with a novel guardassembly, embodyin an adjustably pivoted arm and a plurality of guardsadapted for interchangeable installation on the arm, so as to emcientlyguard the wheel irrespective of the type or size of wheel that may beinstalled in the machine.

The invention further aims to provide a tooth stop device comprising anovel assembly of parts which may be interconnected in a plurality ofdifierent relationships to correctly cooperate with the teeth or otherprojections of the various types and sizes of tools or cutters to beground, and yet which permits ready indexing of the tool to successivelypresent'its cutting edges to the grinding wheel.

Another object is to provide a, grinding machine, having a tablereciprocable with respect to the wheel, with a center device for holdinga tool, and a tooth stop device for successively stepping the tool aboutits axis to present its cutting edges to the wheel and to provide meansfor mounting the tooth stop device either stationarily upon the machineor upon the reciprocable table, to achieve the desired tooth-stoppingaction.

Additional objects are to provide improved headstock and tailstockassemblies, and other grinding machine improvements and refinements tobe hereinafter pointed out.

Further objects will become apparent as the specification proceeds inconjunction with the annexed drawings, and from the appended claims.

In the drawings:

Figure l is a perspective view of the grinding apparatus of theinvention, showing-a side milling cutter in grinding position thereon;

Figure 2 is a similar view of the apparatus, showing a, hand reamer inplace-on the machine;

Figure 3 is a front elevational view of the wheel guard mounting frame.showing a small diameter cup wheel guard in operative position thereon;

Figure 4 is a vertical sectional view through the guard and mountingassembly of Figure 3, looking in the direction of the arrows, the wheelbeing shown in broken lines;

Figure 5 is a view similar to Figure 3, but shows a large diameter discwheel guard in place;

Figure 6 is a vertical sectional view through the apparatus of Figure 5;

Figure 7 is a top plan view showing the auxiliary table assembly of theinvention in place on the main grinder table, with parts broken away andin section to more clearly illustrate the structure;

Figure 8 is a front elevational view of the device shown in Figure 7,parts being broken away and in section to illustrate certain details ofthe structure;

Figure 9 is a vertical sectional view on an enlarged scale, takensubstantially on the line 9-9 of Figure 8:

Figure 9a is a fragmental sectional view illustrating the manner inwhich the tailstock is guided on the auxiliary table;

Figure 10 is a vertical sectional view on an enlarged scale, takensubstantially on the line ill-l 0 of Figure 8;

Figure 11 is an exploded view of the parts of the tooth rest of theinvention;

Figure 11a is a perspective view of a modified form of stop finger foruse with the assembly of Figure 11;

Figure 12 is a longitudinal sectional view illustrating certain parts ofthe tooth rest;

Figure 13 is-a perspective view showing a spiral cutter mounted on theapparatus of the invention by means of a mandrel;

Figure 14 shows the machine with the side milling cutter of Figure 1 inplace thereon, but illustrates the parts from a different angle;

Figure 15 is a perspective view showing the side milling cutter ofFigures 1 and 14 in place on the machine, and with the auxiliary tableswung through 45 to present the bevel side edges of the cutter to thewheel;

Figure 16 is a perspective view of the device shown in Figure 15;

Figure 17 is a perspective view with a form cutter in place on themachine of the invention and with a dish wheel and dish wheel guardinstalled;

Figure 18 is a side elevational view, with parts in section, of aheadstock of modified form, also forming part of the invention; 1

Figure 19 is a view similar to Figure 18 showing a modified form oftailstock also forming part of. the invention;

Figure 20 is a top plan view with parts broken away and in sectionshowing the auxiliary table equipped with a fine adjustment deviceforming part of the invention; and

Figure 21 is a vertical sectional view through the device of Figure 20.

With continued reference to the drawings, wherein like referencecharacters have been employed to designate similar parts throughout theseveral views thereof, and referring first to Figure 1, the grindingmachine to which the invention has been applied comprises a base 9,carrying an upright column II, on which a grinder head i2 is mounted forvertical adjustment by means of a screw 13 and a hand wheel I4. Mountedfor rotation in a grinder frame III, which is rockably carried by headl2, and driven by a motor (not 4 shown) is an arbor assembly I6,carrying a grind-.- ing wheel l1. a cup type grinding wheel being showninstalled in Figures 1 and 2. A micrometer screw I8 is employed toadjust grinding frame Ill up and down with respect to head l2.

Mounted for movement in a horizontal plane toward and away from column His a table slide l9, adapted to be actuated by a hand wheel 2|, thelatter being carried by a screw (not shown) which is threadedlyconnected to the table slide. Mounted for sliding movement on the tableslide at right angles thereto, and actuated by means of a hand wheel 22,is a table 23, having a flat work supporting surface 24 and alongitudinal T- slot 25.

Movement of table 23 is limited in both directions by means of a pair ofstop brackets 26 carried by a rod 21 mounted on the table, andcooperating with a stop screw 28 carried by a boss 28 on slide memberIS.

The grinder structure so far described is fully disclosed and claimed inour co-pending application, Serial No. 467,512, filed December 1, 1942,for Machine tools," which is now Patent No.

2,386,283, issued October 9, 1945, and which may be referred to for amore detailed disclosure thereof.

We have found that, by providing a pilot member A, rigidly anchored tothe grinder table, and auxiliary table B, carrying a headstock C and atailstock D, and mounting a tool rest assembly E upon either theauxiliary table or the main grinder structure, it is possible to convertthe surface grinder of the aforementioned application, or similargrinders, into a tool and cutter grinder which will accurately sharpen awide variety of tools, thereby obviating the necessity of purchasingspecial machine and yet provid ing a structure which is of simple ruggeddesign and which will turn out work of equal if not greater accuracythan the machines designed especially for tool and cutter sharpeningpurposes.

Referring to Figures 7 and 8, auxiliary table B is of elongated form andhas a flat upper surface 3! and a ribbed and flanged lower surface.

Table B is preferably made of ordinary gray iron, and is of such designthat the upper surface thereof may be finished in a simple surfacegrinding operation, there being no elements projecting above thissurface. A longitudinal T-slot 32 extends longitudinally along the topof the table and is utilized to secure the headstock and tailstock inplace in a manner to be hereinafter described. The central part of theunderside of the table is provided with a pair of ribs 33 and 34defining a central space 35 to receive the pilot member A, and (as seenin Figure '7) the forward ends of ribs 33 and 34 are curved to liesubstantially concentrically with the pilot member. A second pair ofribs 36 and 31 on the underside of the table, are concentric with thepilot member, and as seen in Figure 8 have their lower surfaces lying ina plane common with the lower edges of ribs 33 and 34. All of theforegoing bearing surfaces are adapted to seat snugly against the upperside of work table surface 24. Depending from one side of the auxiliarywork table at 01)- posite sides of the space 35 are flanges 39 and M anddepending from the opposite side of the auxiliary work table are flanges42 and 43, it being observed that ribs 33 and 36 merge into flanges 39and 42 and ribs 34 and 3! merge into flanges 4| and 43. The ribs on theunderside of the table also merge into a longitudinally extending boss44, which (as seen in Figure 9) provides the required metal for formingT-slot 32. By reason of the interconnected webs and ribs, and the factthat the lower surfaces of ribs 33, 34, 36 and 3'! are utilized asbearing surfaces engaging the top of the work table, an extremely strongand rugged table unit is provided, and one which transmits the cuttingor grinding forces to the main table in such manner as to avoid anystrains that would result in distorting or springing the partssufliciently to impair the accuracy of the apparatus.

In order to facilitate finishing of top surface 3| of the auxiliarytable in a simple surface grinding operation, a pair of lugs 45 are caston its lower side and have their lower surfaces disposed in the sameplane as the bearing faces of the ribs. "Accordingly, the auxiliarytable may be so supported on the grinding machine during manufacturethroughout its length by the ribs and lugs that it will not undergodistortion during the grinding operation. After manufacture of the tablehas been completed, lugs 45 may be removed if desired.

The novel manner in which the auxiliary table is held in place by thepilot member will now be described. Referring to Figures 7, 8 and 10,the pilot A is of generally disc-like form and is provided with acentral opening 41 (Figure and a cylindrical periphery 48, carryinggraduations 49 (preferably being divided up directly into degreesrunning from zero to 45 in each direction from the zero or parallelposition of the tables shown in Figure 8. The pilot member is secured tothe main work table 23 by means of a pair of T-bolts 5| having headsseating in T-slot 25 of the table and projecting upwardly throughdiametrically spaced openings in the pilot member. A pair of nuts 52,seating in a pair of recesses 53 in the pilot member, are turned on theT-bolts and frictionally clamp the pilot member to the main table. V

The pilot member is accurately positioned with respect to the main tableby means of a pair of keys 55 secured in a longitudinal keyway 56 in theunderside of the pilot member by means of cap screws 5'! and projectingpartially into T-slot 25 adjacent each T-bolt 5|, as seen in Figures 8and 10. Accordingly, by loosening nuts 52, pilot member A may be freelyslid along the top of table 23, being guided by keys 55, and lockedrigidly in any desired adjusted position by tightening nuts 52.

The auxiliary table is secured in place on the pilot member and worktable in a manner seen more clearly in Figures 7 and 10. The auxiliarytable and the pilot member are provided with aligned mating openings 59and 6|, respectively, and after manufacture and grinding of theauxiliary table is completed a trunnion or pivot plug 62 is frictionallyfitted into opening 59 of the table, so as to pivotally project intoopening 6| of the pilot member. If desired, the plug may alternativelybe frictionally fitted into opening iii of the pilot member and disposedin journalling relationship with opening 59 of the table.

From the foregoing structure it is apparent that the pilot member may belocked in the proper longitudinal adjusted position on the table,(preferably in the central position illustrated in Figure 8, so that allof the ribs (33, 34, 3G and 31) may bear upon the upper table surface)and may be locked in place by nuts 52. Also, the auxiliary table isaccurately journalled for rocking movement about an axis normal to thetable surface. The auxiliary table is adapted to 5 be frictionallyclamped to the main table, in any desired angular position, as follows.

Projecting through a pair of openings 64 in the auxiliary table and apair of arcuate slots 65 in the pilot member, and having heads 66seating in arcuate counter bores 67 in the pilot member, are a pair ofbolts (i8. Nuts 69 on the bolts are adapted to pull the table down intotight engagement with the main table, it being observed in Figure 10that when the parts are pulled up tight a clearance 1| exists betweenthe lower face 12 of recess 35 of the auxiliary table, and the uppersurface of the pilot. The provision of this clearance prevents the pilotfrom holding the auxiliary table with its bearing surfaces out ofcontact with the main table, it being understood that only a fewthousandths of an inch clearance is necessary, and that if desired theclearance may be decreased by the use of shims. In order to locate nuts69 below the top surface 3| of the auxiliary table, they are preferablydisposed in recesses H3 at opposite sides of the table.

Secured to the front of the table adjacent front hold-down bolt 58, is ascale plate '25 by means of screws 16 having a reference line 11cooperating with the graduations on cylindrical face 48 of the pilotmember, it being understood that the holes in the plate aresufi'iciently oversize to permit the screws to be loosened and the plateadjusted by minor amounts in either direction to properly calibrate themachine, and when the adjustment has been obtained the screws aretightened to permanently lock it in position.

The auxiliary table is accordingly rigidly mounted upon the main worktable, and by loosening nuts 69 the table may be rocked about thevertical axis of pilot trunnion 62, the desired angular position beingsecure by bringing the appropriate graduation on scale 48 into alignmentwith the zero reference line on plate 15. When the proper adjustment hasbeen obtained nuts 69 are tightened, it being observed that, by reasonof the clearance between the underside of the table and the pilotmember, tightening of the nuts serves to directly pull the auxiliarytable down into clamping engagement with the main table, with thebearing surfaces of ribs 33, 34, 36 and 31 in frictional lockingengagement with the main table. The manner in which the tools or cuttersare adapted to be mounted on centers and presented to the wheel will nowbe set forth.

Referring particularly to Figures 7, 8 and 9, tailstock D is providedwith a fiat face adapted for sliding engagement with the upper surfaceof the auxiliary table, and is guided for movement along it by a pair ofkeys 8i secured in a longitudinal recess 82 in the tailstock by a pairof screws 83, one key being located at each end .of the tailstock. Asseen in Figure 9a, keys 8| project into the upper part of T-slot 32 andare snugly guided therein so as to maintain the tailstock square withthe auxiliary table.

The tailstock is adapted to be frictionally clamped to the upper side ofthe table by means of a. single T-bolt 84, having a head seating inT-slot 32 of the auxiliary table, and a nut 85 bearing against the baseof the tailstock. 'In order to line up the tailstock with the auxiliarytable, it is provided with a pressure member 81 hearing againstaccurately formed faces 88 and 89 on the tailstock and the tablerespectively, it being observed in Figures 7 and 8 that, aside from thecentral break produced by front recess 13,

surface 89 extends throughout the length of the table, so that pressuremember 81 may cooperate with it in any desired longitudinally adjustedposition. A lug BI is also provided on the tailstock adjacent thepressure member for preventing it from tending to rotate and rock thetailstock out of firm engagement with the table. The pressure member isheld in place by means of a thumb screw 92 threaded onto a stud 93secured in the tailstock base.

It is accordingly apparent that the tailstock may he slid into anydesired position along the table and when the desired position has beenattained thumb screw 92 is tightened, so as to cause the tailstock to bepulled toward the front of the table. This action causes keys 8I toengage the front wall of T-slot 32, taking up any lost motion betweenthe keys and the slot and accurately aligning the tailstocks with thelongitudinal axis of the table by a T-square" action. Nut 85 is thenturned home to' rigidly clamp the tailstock in place.

Mounted for reciprocation in the upper end of the tailstock is a center95, urged toward work gripping or loading position by a. compressionspring 96 seating against a cap 91 and adapted to be locked in place bya set screw 98. The center 95 is adapted to be retracted by means of aneccentric 99 seating in a transverse slot I M in the center and carriedby a shaft I02 having a reduced portion I03. The shaft is adapted to belocked in place by a set screw and lock nut assembly I04 having areduced end seating in groove I03. The shaft is adapted to be rocked bymeans of a lever I 05 secured to the end of the shaft. In the positionsshown in Figure 8 the parts are in loading or work gripping position,and if desired screw 98 may be tightened to lock center 95. When it isdesired to remove the work from the centers it is merely necessary toloosen screw 98 and rock handle I05 counterclockwise, which, throughshaft I02, eccentric 99 and slot IOI, retracts the center against theaction of spring 96. A lubricant fitting I 05 may be provided foradmitting lubricant to the center and associated parts.

The headstock is supported upon and secured to the auxiliary table in amanner similar to the tailstock, and therefore similar referencecharacters, with the subscript c," have been employed to designate thesimilar parts and they will not again be described. The headstock isprovided with a simple cylindrical portion I08 in which a center I09 isadapted to be locked in longitudinally adjusted position by a set screwII I.

Referring particularly to Figures 3, 4, 5 and 6, and referring first toFigure 4, grinder frame I is provided with an end face disposedsubstantially normal to the axis of rotation of the wheel, designated asI I2 in Figure 4, to which is secured, preferably by means of threescrews II3, a dual purpose foundation or frame member II4, having a pairof arcuate slots I I and I I6 at its upper end and a pair of lugs I I1and H8 at its lower end. The lugs are reinforced by angular webs H9 andthey are each provided with an opening I2I for receiving a tooth-stopsupporting screw, as will be pointed out hereinafter. Adapted forinterchangeable installation in either slot H5 or slot H6 is a boltassembly I22 carrying a. short crank arm I23 terminating in a forwardlydirected pin or shaft I24. As seen in Figure 3, bolt I22 is providedwith a square head I25 seating in an elongated recess I 26 in crank armI23, so that nut I20 may be loosened and link I23 slid and rocked intoany desired position with respect to bolt I22, and then looked in place.

Pin I24 is preferably tightly fitted into link I23 so as to benon-rotatable therein and is adapted to interchangeably support any oneof a plurality of wheel guards. This appreciably widens the scope ofusefulness of the machine because it permits either cup, or dished orperipheral grinding wheels of different diameters to be installed, aswell as aifords a wide range of adjustabillty of the guards with respectto the wheel, depending upon the particular type of wheel guardingrequired by the work being handled.

In Figures 3 and 4 the guard of Figures 1 and 2 is shown in place on themachine, in proper guarding relationship to the wheel. The guardcomprises a guard portion I20 of generally semicylindrical form, havinga front flange, and an ear I29 which freely fits over pin I24 and isadapted to be locked in place by a wing screw I3I Referring to Figure 2,the parts are so adjusted as to dispose guard I28 in comparatively closeguarding relationship with wheel I1 and this relationship is alsoillustrated in Figure 13. In Figures 14 and 16, the guard has beenremoved and reversed end for-end and reinstalled, with the flange on theinside of the wheel, to make room for the tool in the particulargrinding operation illustrated, it being understood that while lateralguarding of the wheel is no longer present, the cylindrical portion ofthe guard is still effective to guard the operator.

In Figures 5 and 6, the guard foundation assembly is illustrated havinga modified guard I33 installed thereon. A lug I34 on the guard fits overpin I24 and is locked in place by a wing screw I35, it being observedthat nut I20 has been loosened and link I23 rocked upwardly into theposition shown, to compensate for the increased diameter of the wheeland guard. The parts are then locked in place to securely hold the guardin operative position with respect to the wheel. Referring to Figure 17,guard I33 is shown in proper guarding relationship to a dished form ofwheel Ila, it being observed that the guard fits down closely around thewheel and that the front flange adequately guards the operator.

While any number of different size and type of guards may be providedfor interchangeable installation on pin I24, the two guards shown havebeen found to take care of the various sizes and types of wheelsgenerally used, and by reason of the ready adjustability of the guardtoward and away from the wheel to meet various grinding conditions, thereversibility of the guards and also the adjustability of the supportingarm, the wheel may be efficiently guarded for all grinding operations.

The invention also embodies a novel work stop device adapted tocooperate with the teeth or other projections on the work and maintainit in fixed angular relationship to the grinding wheel during thegrinding operation, and yet permits ready indexing.

Referring particularly to Figures 11, 11a. and 12, the device comprisesa base member I-4I, having a longitudinal slot I42 and terminating atone end in a head I43 having a pair of intersecting openings I44 and I45which preferably are of the same diameter. A set screw I46 threaded intothe head is adapted to lock a member placed in either aperture.

The base member is adapted to be secured in place on various parts ofthe machine by means of a T-bolt I41 and a nut I48. For instance inFigure 2 the'base is secured to the face of the auxiliary table by meansof the bolt I41 seating in the T-slot 32, while in Figure 13 the basemember is secured to ear I I1 of foundation memher I I4, so that thework is movable with respect to it.

Referring again toFigure 11, cooperating with head I43 of the base is arod I49 having an enlarged end providing a. transverse opening II. RodI49 may be mounted directly in opening I44 or I45 and locked in place byset screw I46. However, in handling certain classes of tool and cuttergrinding, it is desirable to offset the rod from the base and we haveaccordingly also provided a pin I52 having a head providing across boreI53 of sufiicient size to receive rod I45, and a tlireaded lower endI54. Rod I49 is adapted to be installed in bore I53 and pulled down intoengagement with V-notches I55 in a collar I56 by means of a nut I51threaded on the reduced portion I54 of pin I52, it being observed thatthe shank of the pin is of substantially the same diameter as openingsI44 and I45, whereby it may be installed in either opening. In thisinstance, however, it is unnecessary to lock pin I52 in place withsetscrew I46, as the frictional force set up by nut I51 is usuallysuiiicient to frictionally lock the parts.v

Adapted to be inserted in opening I 5| of rod I49, and locked in placeby means of a set screw I58, is a rod I59 having a cross bore I6I. Re-'ferring more particularly to Figure 12, rod I59 is adapted to snuglyreceive a thimble or sleeve I62 having a flange I63 into which ascrewI64 is threaded. Mounted for sliding movement in sleeve I62 is thethreaded shank I65 of a stop finger supporting head I66, the shankhaving a longitudinal groove or keyway I61 cooperating with a reducedend I66 of screw I64 to restrain it against rotation within the thimble.Threaded onto the shank is a nut 69, which bears against the upper faceof fian e I63 and is adapted to thread the shank upwardly in thethimble, the

shank being shown in its lowermost position in Figure 12.

Head I66 is provided with a recess "I and pivoted therein on a pin I12is a finger supporting member I13. The finger support is urged in aclockwise direction by a spring I14, seating in recesses in the memberand head I66, toward an adjustable stop screw I15 threaded into thehead. Member I13 is also adapted to be locked against rocking movementby means of a set screw I 11 threaded intohead I66 and cooperating witha depression I18 in member I13.

Member I 13 is adapted to interchangeably support either the straightfinger I19 shown in Figure 11, or the hooked finger I8I shown in Figure11a, the fingers being secured in place by a screw I82 threaded into theend of member I13.

Taking up the grinding operations illustrated in the several perspectiveviews, we have shown in each instance a spacer block I96 interposedbetween the head and tailstock and the auxiliary table. Each block isprovided with a rib on its lower face adapted to seat in the T-slot ofthe auxiliary table and has a longitudinal slot in its upper faceadapted to receive the head and tailstock keys. In this instancepressure members 81 and 81c are mounted directly on the spacer blocks.While it is to be understood that blocks I96 need only be employed whenlarge diametered work is being handled, they may, if desired, be left inplace as permanent parts of the machine.

Referring first to Figure 2, the machine is illustrated as having asimple hand reamer I9I mounted in place between centers 95 and I69; theauxiltool edges to be ground exactly parallel to the path of travel ofthe main table; and the straight finger stop I19 is shown as cooperatingwith the teeth of the reamer for stepping it around as the grindingoperation proceeds. Stops. 26 are so adiusted on rod 21 as to cause stoppin 26 to limit the travel of table 23 to that required to grind thetool. The head and tailstock and spacer block assemblies are secured tothe table by bolts somewhat longer than those shown in Figures 8 and9.

In this instance base member I is clamped directly to the top of theauxiliary table by bolt I41 and rod I59 is clamped directly in openingI45 by means of set screw I46. The stop assembly is directly carried byrod I59 and is so oriented as to be stopped by screw I15 when the fingerpivots toward the front of the machine, with the result that the operatowith each passage of the work need only rotate the reamer an angulardistance corresponding to one tooth space, and during this "indexingoperation the reamer will pivot the finger outwardly against the actionof spring I14 into the proper position to stop the next tooth or cuttingedge in the proper grinding position. It is to be understood that, ifthe work is not properly ground by single passage across the wheel face,handwheel 2| may be rotated to move slide table I9: work table 23; andauxiliary table B'bodily toward the grinding wheel by the necessarydistance to take off the-required amount of metal to restore the cuttinedges of the tool. It is to be understood that during grinding theoperator will grasp the work and urge it into firm contact with thestop.

- As is well understood in the grinding art, it is often desirable tocut with only a portion of the wheel face, the grinding face often beingtilted from one-half to one degree from the plane of the surface beingground, which prevents the back edge from dragging; eliminates anypossibility of burning, and results in a much better job. In the presentmachine this cooking or tilting of the wheel is eifected by looseningthe bolt for the column and turning the column through the requiredangle (usually from onehalf to one degree) to incline the wheel face ata similar angle with respect to the path of travel of the main table.

It should be observed that in this particular setup of the tooth stop,neither rod I49 norpin I52 and itsassociated parts is employed. Thenumber of parts employed in any case will depend upon the conditions ofeach setup. and

and peripheral cutting edges I and 45 bevel corners I96, the parts beingshown in Figures 15 and 16 in proper position to grind the 45 cornersand in Figures 1 and 14 in position to grind the peripheral edges I95.

Referring first to Figures 1 and 14, the auxiliary table is set on zero,to that it will move parallel to the plane of the wheel. Guard I26 hasbeen removed and replaced in reversed position on shaft I24, and spacerblocks I 96 are again used to raise the head and tailstock the properdistance to provide the required swing of the tool.

Base member I of the finger stop assembly is secured directly upontheauxiliary table by means of bolt I41 and nut I48 and in this instancerod I59 is mounted directly in opening I45 of the base and lockedtherein by screw I46. Rod I59 carries thimble I52 of the stop assembly,and in this instance the hook form of stop IN is secured to carrier I13in an inclined position, so as to lie directly under the tooth beingground. The head IE is so disposed that arm I13 is freely pivotal towardthe wheel, so that upon completion of the grinding of one face the toolmay be rotated clockwise (Figure 14) to bring the next face intogrinding position, it being understood that in all of the grindingoperations, the operator will exert sufiicient pressure upon the toolbeyond the tooth stop then re-engaging the stop to maintain the stoppedtooth in firm engagement with the tooth stop, thereby predetermining theamount of metal the wheel will remove from each tooth.

When all of the peripheral edges I95 have been sharpened in the mannerJust discussed, the parts are then brought into the relationship shownin Figures 15 and 16, as follows; The tool and mandrel are removed fromthe centers and reversed end-for-end, so as to incline the teethupwardly adjacent the wheel; nuts 59 are loosened and the table rocked45, as determined by the graduations on scale plate I5. It is alsodesirable to recombine the parts of the tooth lock device as follows. Asseen in Figures 15 and 16, base MI is clamped to the auxiliary table inreversed position from Figure 14, and pin I52 is inserted in opening I45in the base and rigidly clamps rod I53 by means of collar I56 and nutI51. Hook finger I8I is inclined as before, but in this instance engagesthe top of the teeth as they are successively brought into grindingposition and it is accordingly necessary for the operator to exert aclockwise rotative force upon the tool during the grinding operation.

When it is desired to grind the tapered corner I96 on the other side ofthe cutter, it is merely necessary to rock the auxiliary table to itsopposite 45 limiting position and to move the tooth stop finger assemblyonto the other side of the tool.

In Figure 13 there is shown a helical cutting tool I carried by amandrel 202 between the centers inoperative grinding relationship withwheel II. In this setup of parts the auxiliary table is again set onzero, so as to travel exactly parallel with the cutting face of thewheel, but as the teeth'203 of the cutter are of helical form and mustbe rocked during grinding, a somewhat different stop arrangement isemployed.

Base member MI is clamped to the underside of lug II! of the guardfoundation by means of bolt I41 and nut I48, so as to maintain the stopassembly stationary while the work is being moved across the wheel face.Pin I52 is secured in vertical opening I44 in base MI and is securedtherein by nut I51. Rod I59 is located in opening I53 of pin I52 andclamped against collar I55. Carried in opening IGI of rod I59 is aspecial form of tooth stop which consists of a plain rod 204 held inposition by set screw I60 and engages between the teeth of the cutter insuch manner that when the auxiliary table is moved past the wheel thecutter will be rocked about the centers the necessary amount to maintainthe surface to be ground in the proper relationship to the cutting'faceof the wheel, it being understood that the operator will, as before,exert with the next tooth to be ground.

In Figure 17 there is disclosed a forming tool 205 carried by a mandrel208 between the centers of the headstock and tailstock, and is adaptedto be ground by a dish form of wheel I'm. In this instance the auxiliarytable is again set on zero so as to carry the work in a path at rightangles to the wheel axis and a re-arrangement of the parts of the stopmechanism is also utilized. The tool is provided with inclined toothfaces 201, and in order to grind them properly a dish wheel is employed.

Referring to the tooth rest or stop mechanism, base MI is secureddirectly to the face of the auxiliary table by bolt I41 and nut I48, andcarried by pin I52, inserted through opening I45 in the base, is rodI49. The latter in turn supports rod I59 to which the stop thimble I52is secured. In this instance the straight stop finger I79 of Figure 11is secured in place by screw I82 and engages directly behind the toothbeing sharpened, head I66 being so oriented that the finger will freelypivot upwardly and allow a new tooth to be presented to the grindingwheel in response to indexing movement of the tool.

In Figures 18 and 19 we have illustrated a modified form of head andtailstock also forming part of the invention. Referring first to Figure18, the.

base is of substantially the same form and is secured to the auxiliarytable in a manner similar to the tailstock previously described. As seenin Figure 18, the headstock 2I2 is symmetrical in form, having anenlarged head portion 2I3 provided with a longitudinal bore 2I4communicating with an opening 2I5. At each end of portion 2I3 isprovided an ear 2I6, and each ear is split in a vertical plane by amilling cutter, the bottom of the cuts being indicated by the line 2".The

- ears are provided with screws 2I8 for tightening Ill) the splitportions and locking the center H9 in adjusted axial position therein.In this instance the center is shown as made up of a major portion 2I9of relatively inexpensive and noncritical material and a hardened alloyinsert 22I, which forms the actual center.

Referring to Figure 19, the tailstock 223 is made from identically thesame pattern and is basically the same in all respects, having anenlarged portion 224, a central bore 225 communicating with an opening226, and at each end is formed an ear 227, the ears being split by amilling operation along the lines 228. In this instance however center229 is provided with a longitudinal groove 230 cooperating with a washer23I to prevent rotation of the center and yet permit free endwisemovement. 7

Center 229 is adapted to be locked in adjusted position by a cap screw232 threaded into one ear 221, washer 23I being sufficiently thin as tonot interfere with the clamping action. Center 229 is urged toward workgripping position by a compression spring 233 reacting against a cap 234securely clamped in the tailstock by a screw 235 cooperating with theother pair of ears 221. The center is adapted to be retracted by a rod236 projecting through cap 234 and threaded into the center. Cooperatingwith a lock nut and washer assembly 231 on the free end of rod 236 isthe forked end 238 of a lever 239 which is pivoted on a pin 24I carriedby a pair of supports 242 formed on cap 234.

In the fully released position shown in Figure 19 the forked end oflever 239 lies against the rear face of cap 23!, and, when it is desiredto retract the center, a handle 243, secured to lever 239 is rockeddownwardly, which causes the forked end to move the center to the right,against the action of spring 233.

In Figures 20 and 21 we have illustrated a fin adjustment applied to theauxiliary table, which makes it possible to accurately adjust the tableto bring the tool into correct alignment with the wheel even whenextremely small angles are involved, without resort to tapping or otherexpedients.

Provided on the interior of the side webs of the auxiliary table bothfront and rear are bosses 25l and 252 into which are threaded a pair ofadjusting screws 253 and 254 respectively, which may be manuallymanipulated by cross pin handles or the like. The screws preferably liein a common horizontal plane closely adjacent the level of the top ofmain table 23, and cooperate with a stop 255 pivoted on a pin 255carried by a slide member 251. The latter fits into keyway 25 and hasshoulders 258 adapted to be forced into tight engagement with theundersi'des of the over-hanging portion of the keyway by a set screw 259threaded into the slide and bearing against the bottom of the keyway.Stop 255 may be pivoted clockwise out of the path of screws 253 and 254when it is desired to adjust the machine without them, or when the tableis adjusted through angles which are too large to permit use of theadjusting screws.

Accordingly, when it is desired to employ the fine adjustment, as forinstance when grinding tapered reamers or other tools which may not betrue, stop 255 is swung into its full line position; the table isadjusted into the approximate position desired; and the table T-boltnuts 52 tightened sufliciently to exert a frictional drag. Screw 253 or254, depending upon the direction the table must be rocked, is'thenscrewed in. This causes the selected' screw to engage the stop and forcethe table to turn about its axis against the resistance of thefrictional drag. When the adjustmentis complete, nuts 59 are tightenedto rigidly lock the auxiliary table in place. In the drawings bothscrews have, for convenience, been shown engaged with the stop,understood that in practice only one screw will be engaged, the otherbeing backed oil to allow the tableto turn. It is also to be understoodthat while we prefer to employ a single stop, in combination with frontand rear screws, if desired, both screws may be mounted at the front ofthe table on opposite sides of the pivot and cooperate with separatestops at opposite ends of the table, without departing from the spiritof the invention.

In addition to permitting fine adjustments to be carried out, the novelscrew and stop assembly is also advantageous in many other classes ofgrinding as it makes it possible to set up the parts with the surface tobe ground parallel to the travel of the main table, irrespective ofshape.

From the foregoing detailed disclosure it is apparent that the inventionprovides a novel auxiliary table which may be readily installed on thetables of present day surface grinders, for the purpose of convertingthem to tool and cutter grinders, and which may be adjusted about anaxis normal to the table surface to locate the tool or cutter at theproper grinding angle, and also provides novel head and tailstock but itis to be ous grinding l4 assemblies; a tooth rest or stop of novelconstruction; and guard and guard supporting assemblies which are sodesigned as to permit a number of diiIerent guards to be interchangeablymounted on the support and affords adjustment of the guards into variousguarding positions with respect to the wheel, to permit varioperationsto be carried out without from the guards, and at the same maximumprotection to the operainterference time affords tor.-

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention. beingindicated by the appended claims rather than by the foregoingdescription, and, all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a machine tool having a grinding wheel, a slide table and ahorizontally reciprocal, work table providing a horizontal, planar worksupporting surface below the grinding wheel, an attachment comprising apilot member; means for securing said pilot member to said work supporting surface; an auxiliary work supporting table overlying said pilotmember and resting on said work supporting surface in vertically spacedrelationship to said pilot member;- pivot means mounting said auxiliarywork supporting table for rocking movement about a vertical axis on saidpilot member; means on said pivot means for drawing said auxiliary worksupporting table down into clamping engagement with said work supportingsurface; and means on said auxiliary work supporting table for holding awork piece thereon in position for presentation to said grinding wheel.

2. The combination defined in claim 1 wherein said auxiliary worksupporting table is provided with a fiat upper face disposed parallel tosaid work supporting surface and on its underside is provided with atleast two transverse ribs, one located each side of said pivot means,said ribs having lower faces located in a common plane and adapted toclampingly engage said work supporting surface in any one of a pluralityof adjusted angular positions about said vertical axis.

3. In a grinder having a flat, T-slotted work supporting table, a toolholder comprising a pilot member of disc-like form provided atdiametrically opposite points with a pair of securing devices coacting.with the T-slot of said work'supporting table and operable to secure itin frictional clamping engagement therewith; means, located adjacenteach of said securing devices, and projecting into the slot of said worksupporting' table, for accurately keying said pilot member thereto; anauxiliary work supporting table member overlying said first mentionedwork supporting table and having a downwardly projecting portion locatedeither-side of said pilot member and resting on said first mentionedwork supporting table; a pivot pin, rigidly secured in an opening in oneof said members and snugly journalled in an opening in the other member,mounting said auxiliary work supporting table member for limited rockingmovement; and clamp means cooperating with said pilot member and saidauxiliary work supporting table member

